This is a hilarious gag! When you have this gizmo handy you can apparently pop your neck or back and it will make a horrible bone crunching sound. This little plastic device can easily be hidden in your hand. When desired grab your chin, with the neck cracker hidden in your hand, and give your head a slight twist as you crunch down and collapse the plastic gimmick. Everyone close by will hear what they think are bones popping. I sometimes do the same with my back. Better yet, grab someone else’s head and give it a slight twist to supposedly crack their neck. This gag is cringe-worthy and gives people the heebie-jeebies.